1. Field of the Invention
This invention relates to an apparent viscosity measuring apparatus, and more particularly to an apparatus for conducting a method of testing an apparent viscosity.
2. Description of the Prior Art
An apparent viscosity of grease serves as one criteria when a pressure loss in a grease feed during a concentrated grease feed, performance of an initial torque or a running torque or a bearing and the like are evaluated.
As prescribed in JIS (Japanese Industrial Standard) K-2220 and ASTM-1092, this method of testing the apparent viscosity of grease is intended for that, when a cylinder connected thereto with capillary tubes is filled up with test grease and this test grease is pushed out of any one of the capillary tubes, pressure applied to the cylinder is measured to thereby seek the apparent viscosity of the test grease.
In this case, in general, several types of capillary tubes (four tubes, normally) different in diameter from one another are used on a test sample, and measurements are made with the shearing speed being changed.
However, only one capillary tube has been connected to a cylinder in the conventional measuring apparatus, thereby presenting the following disadvantages.
Namely, from necessity of conducting measurements by using several types of capillary tubes and changing the shearing speed, it is disadvantageous that capillary tubes should be exchanged one after another during measuring.
In general, since the cylinder is housed in a constant temperature bath and immersed in a heat transfer medium such as methanol so as to hold the temperature of grease at a predetermined temperature, the heat transfer medium must be discharged each time the capillary tube is exchanged, and moreover, a time duration required for conditioning the heat transfer medium received in the constant temperature bath again to the predetermined temperature is wasteful.
Further, in order to exchange the capillary tube without the discharge of the heat transfer medium from the constant temperature bath, it is necessary to take the cylinder out of the constant temperature bath, thus making the burden too heavy for a worker.
Anyway, with the conventional apparatus, in measuring one test sample, much time and labor have been required, the handling thereof has been extremely troublesome and the measuring efficiency has been very low.
When a test sample, a possible measured pressure of which is beyond imagination, is measured, a pressure gauge may have a scaleover to result in a failure in measurement, thus presenting such an inconvenience that a measurer should watch the apparatus during measuring and change over to a proper pressure gauge as necessary.